The sustainable resveratrol-based phthalonitrile was used in the preparation of E-glass fiber-reinforced phthalonitrile composite panels fabricated by hot pressed prepreg consolidation with bis[4-(3-aminophenoxy) phenyl] sulfone (m-BAPS) as the curing additive. This amorphous monomer exhibited excellent viscosities at temperatures below 200 degrees C, which is applicable to standard processing conditions. Rheometric measurements were used to evaluate the cure of the composite as a function of the postcure conditions. The composite retains > 95% of its room temperature storage modulus up to 450 degrees C based on these postcuring parameters. More importantly, flammability performance of the composite-which was determined in terms of ignitability, heat release, and mass loss rate-excels over other state-of-the-art polymer/glass composites. Even under the most extreme heat fluxes (e.g., 100 kW.m(-2)), the composite performs exceptionally well suggesting that resveratrol-based phthalonitrile composites can be used in fire-resistant applications. Published 2018.